const addBtn = document.getElementById('addBtn');
const subtractBtn = document.getElementById('subtractBtn');
const number = document.getElementById('number');

addBtn.addEventListener('click', function() {
    number.textContent = parseInt(number.textContent) + 1;
});

subtractBtn.addEventListener('click', function() {
    number.textContent = parseInt(number.textContent) - 1;
});

// 勾选实现
const select = document.getElementById('select');
const checkmark = document.getElementById('checkmark');

select.addEventListener('click', () => {
    if (checkmark.style.display === 'none') {
        checkmark.style.display = 'block';
    } else {
        checkmark.style.display = 'none';
    }
});